It all looked promising last night at the National Stadium, as the crowd gradually warmed to several rounds of the Kallang Wave before the match.

But the Lions fans - save for a section near the giant Singapore flag at the East end of the 55,000-seater arena - were mostly muted when the reigning Asean Football Federation (AFF) Suzuki Cup champions fell 2-1 to Thailand in their opening match.

While vociferous blue-clad supporters of the War Elephants filled about half of the away section, about half of the seats in the home section were filled when the match kicked off at 8.11pm, after the respective national anthems.

The crowd gradually swelled to 32,148 in the first half, but the away section made themselves heard with their coordinated "Thailand, Thailand" chants.

Fans whom The New Paper spoke to gave several reasons for the less-than-full house, with the English Premier League match between Liverpool and Crystal Palace taking place at 9.30pm last night.

Public officer Liew Shi Xiong said: "The atmosphere at the Jalan Besar Stadium was much better because everyone was packed much closer.

The 27-year-old said: "It was always full at Jalan Besar in the past and fans had difficulty getting tickets because of the smaller capacity.

"Also, I think we fans have lower expectations of the team this tournament, since we are in the Group of Death with Thailand, Myanmar and Malaysia."

The Kallang crowd was silenced in the ninth minute when Mongkol Thosakrai put the Thais ahead.

But Kallang roared 11 minutes later, when Khairul Amri ghosted into the six-yard box ahead of a Thai defender to nod home an inch-perfect Shaiful Esah cross from the left.

Except for the vocal Singapore section, cheers from the rest of the Lions supporters gradually petered out, raising their volume momentarily whenever the likes of captain Shahril Ishak, Khairul Amri and Faris Ramli came close to finding the back of the net.

Things picked up for a short while in the 75th minute, when the vocal Singapore section's synchronised clapping spread throughout the stadium for a couple of minutes.

That didn't last though, and it was the Thai supporters who had the last laugh when Charyl Chappuis scored from the penalty spot in the 89th minute, after Safuwan Baharudin handled the ball in the box, to give the visitors a precious 2-1 win.

Pockets of home fans started for the exits as soon as the Thais were 2-1 up, but they vowed to be back for the Lions' next game against Myanmar on Wednesday at the National Stadium.

Nizam Mohd Salleh said: "It is just the start of our journey at the new stadium and we are still warming up.

"We will get better in the second and third game. We will be back to support them."